本研究以脫層石墨(exfoliated graphite nano-platelets)和膨脹性石墨(expandable graphite)作為乙烯-醋酸乙烯酯(EVA)的阻燃劑,利用雙輥混煉機和高分子熔融法製備出乙烯-醋酸乙烯酯/脫層石墨/膨脹性石墨之高分子複合材料。 在膨脹性石墨於高、低添加量下(20wt.%、12wt.%),使用少量的脫層石墨去作一個取代,進而觀察其熱性質與燃燒行為的變化。分別使用了限氧指數儀、熱重分析儀、垂直燃燒檢測、圓錐量熱儀去探討其燃燒與阻燃行為並做分析。 實驗結果顯示,添加石墨材料的試片確實能降低其熱釋放率和遮光係數。在阻燃效率方面是膨脹性石墨優於脫層石墨,因其受熱時會產生膨脹性炭層對於阻熱、抑煙、隔絕氧氣方面均有相當的作用;在熱穩定性方面是脫層石墨優於膨脹性石墨,因其熱裂解溫度較高且受熱時會產生一層具有隔絕作用的薄膜。 綜合上述的實驗結果,以添加膨脹性石墨18wt.%、脫層石墨(5μm)2wt.%下是最好的,其LOI值達28.5、UL-94達V-0等級、TGA熱裂解溫度提升22.1℃、熱釋放率降到288.8(kw/m2)、遮光係數為1.89(1/m)。
This research uses exfoliated graphite nano-platelets and expandable graphite for EVA’s flame retardants, which was prepared by polymer melt intercalation and twin-roll mixing mechanism of EVA/exfoliated graphite nano-platelets/expandable graphite polymer composites. In the expandable graphite under high and low dosage (20wt.%, 12 wt%) with a small amount of exfoliated graphite nano-platelets as substitute, and then observing its thermal properties and combustion behavior change. LOI, TGA, UL-94, and Cone were used to investigate the combustion and flame-retardant behavior to analysis. The experimental results show that the addition of graphite materials samples can indeed reduce the rate of heat release and the extinction coefficient. Flame-retardant effect of expandable graphite is better than the exfoliated graphite nano-platelets, due to the expansion carbon layers has a considerable role for thermal resistance, inhibition of the smoke, and the absence of oxygen. On the other hand, the thermal stability of exfoliated graphite nano-platelets is superior to the expandable graphite because the high temperature of pyrolysis will produce a thin film which produces an isolation effect. By taking the above experimental results, it is shown that adding 18wt.% expandable graphite and (5μm)2wt.% exfoliated graphite nano-platelets produces the best experimental results. Its LOI value of 28.5 and UL-94 to V-0, TGA pyrolysis temperature to promote the 22.1℃, the heat release rate is reduced to 288.8(kw/m2) and extinction coefficient of 1.89(1/m).